Foldable boxes with interlocking cover structure



G. s. SEXTON 3,246,829

FOLDABLE BOXES WITH INTERLOCKING COVER STRUCTURE April 19, 1966 Filed Dec. 28, 1962 5 2.5/76 ffa.

IN VE NTOR. 5. 5ru4er Saw-0N flrraewa 'zontal foldlin'es. side Wall panels which are bounded by vertical and horizontal foldlines (along which they are hingedly connected United States Patent 3,246,829 FOLDABLE BOXES WITH INTERLOCKING COVER STRUCTURE G. Stuart Sexton, Darien, Conn., assignor to International Paper Company, New York, N.Y., a corporation of New York Filed Dec. 28, 1962, Ser. No. 248,013 6 Claims. (Cl. 229-31) This invention relates to a folding carton or tray. More particularly, it relates to a folding carton, which can be made from a blank formed on a sheet material such as paperboard, having web corners and novel means by which to lock such corners and the carton walls into, position upon erection of the carton. Such carton has particular utility in the field of frozen food packaging, since its corners aid in making the carton leak-proof.

Folding cartons having Web corners and devices for locking such corners inthe erect position are known to those skilled to the art. However, it has been found that many of these derive from carton blanks which are not substantially rectangular in shape and are, therefore, wasteful of blank material or the sheets or webs from which they are cut or stamped. 'Moreover, they derive from blanks which include in their designs provisions for awkwardly extending protuberances, e.g., tongues and tabs, which, because they are in no sense concealed or protected, can be accidentally torn or damaged in untimely fashion. US. Pat. Nos. 2,909,105 and 3,008,626 present examples of this type of disadvantage.

It has now been found that such disadvantages can be overcome and that an appreciably less wasteful and accident-prone web corner carton with locking means can be produced. Broadly, this is accomplished by making a blank of sheet material for folding into a carton which, when finished, comprises a substantially flat rectangular unit having a bottom panel bounded by vertical and hori- Opposing end wall panels and opposing to the bottom panel) and end and side outer edges are provided, as are first web corner panels bounded by vertical foldl-ines (along which they are hingedly connected to the end wall panels), diagonal'foldlines, and first corner outer edges and second web corner panels bounded by horizontal foldlines (along which they are hingedly connected to the side wall panels), the diagonal foldlines (along which they are hingedly connected to the first web corner panels), and second corner outer edges. (Further, there are provided means, e.g., slits or cuts, by which devices for looking the web corner panels in place in the erected box or carton are formed. Thus, along the end outer edges, slits and, perhaps, short scores are employed to de'tfine and produce inwardly extending tongues; along the first corner outer edges, cuts are employed to make inwardly extending apertures; and, along the second corner outer edges, slits and, optionally, short scores cooperate to yield inwardly extending locking tabs.

Preferably, the tongues on the end wall panels of the blank of the present invention diminish in width, and in discrete stages, so as to fashion small wings or ears on the sides of the tongues as they extend inwardly from the end outer edges into the end wall panels. Again, it is prefer- .able for the apertures and the locking tabs to diminish in width as they extend inwardly from the several corner outer edges, for them to have substantially the same dimensions, and for them to lie substantially equidistantly from the diagonal foldlines immediately separating them. Then, when the tongues are made to be wider along the end outer edges than either the apertures or the tabs along the corner outer edges and when the tongues are suitably 3,246,829 Patented Apr. 19, 1966 disposed along such end outer edges, it will follow that in the erected and locked carton wherein the end and side wall panels are perpendicular to the bottom panel and each other, the first web corner panels are disposed adjacently to the end Wall panels, and the second web corner panels are disposed adjacently to the first web corner panels-the tongues are disposed in the apertures and beyond, .i.e., in the spaces left when the locking tabs are moved out of the sheet material from which they are cut or slit and into the interior of the carton, and the locking tabs (primarily because of the habit of the sheet material) impinge or abut against the tongues, holding them, with the aid of their wings, in such apertures and spaces.

For a better understanding of the blank and carton of the present invention, reference should be had to the attached drawings in which FIGURE 1 is a plan view of a preferred embodiment of the blank of the present invention.

FIGURE 2 depicts a partial isometric view of the carton made from the blank of FIGURE 1;

FIGURE 3 shows a partial isometric view of the blank of FIGURE 1 as it is being folded into the erected carton of FIGURE 2;

FIGURE 4 shows a sectional side view of the carton of FIGURE 2, taken along line 4-4; and

FIGURE 5 shows a partial isometric view of the carton made from the blank of FIGURE 1 with emphasis on its cartons end closure and end closure opening means.

As seen in FIGURE 1, the .blank of the present invention is made up of a bottom panel 10; opposing end wall panels 11 and .12; first web corner panels 13, 14, 15, and '16; second web corner panels 17, 18, 19, and 20; and, opposing side wall panels '21 and 2-2. These are all hingedly connected along vertical foldlines 23 and 24; horizontal foldlines 2-5 and 26; and, diagonal foldlines 27, 28, 29, and 30.

End wall panels 11 and 12 have end outer edges Ma and 12a; first web corner panels 13, 14, 15, and 116 have corner outer edges =13a, 14a. 15a, and 16a; second web corner .panels 17, '18, 19, and 20 have corner outer edges 17a, 18a, 19a, and 20a; and, side wall panels 21 and 22 have outer edge 22a and, in place of an outer edge, foldline 21a linking panel 21 and lid member 50 and its flaps 51, 52, and 53.

Alon-g outer edges Ma and 12a of end wall panels 11 and 12, FIGURE 1 shows tongues 11b and 12b which are formed, on each side, by connected cuts 11c, 11d, and He and 12c, 12d, and I122 and, on the ends thereof away from outer edges 11a and 12a, by scores 11f and 12f. It will be seen that the disposition of the connected cuts causes tongues 11b .and 12b to diminish in width as they extend into end wall panels 11 and 12 and to do so in three discrete stages (denoted by the letters 0, d, and e). The consequence of such staging, or, perhaps, staggering, is the formation of wings '11g and 12g on tongues 11b and 12b.

FIGURE 1 also shows apertures 13b, 14b, 15b, and 16b cut into first web corner panels 13, 14, 15, and 116 inwardly from outer edges 13a, 14a, 15a, and 16a. The sides of such apertures are seen to converge slightly. Again, the figure shows locking tabs 17b, 18b, 19b, and 20b cut into second Web corner panels '17, 18, 1 9, and 20 inwardly from outer edges 17a, 18a, 19a, and 20a and the convergence of the sides of such tabs. Beyond this, the substantially equal dimensions of the apertures and tabs and the substantial equidistance of, for example, aperture 14b and tab 1811 from diagonal foldline 28, Le, the foldline immediately between them, are shown.

The .proper folding at the carton corners of the blank of FIGURE 1 is shown in progress in FIGURE 3 and completed in FIGURE 2. Upon the erection of end wall panel 11 and side wall panel 21, for instance, first Web corner panel 13 and second web corner panel 17 are brought into a contiguous or abutting relation along diagonal foldline 27 so that panel 13 is disposed adjacent to or impinging against the carton inside of panel 1 1 and panel 17 is disposed adjacent to or impinging against the cartoninside of panel 13. A similar juxtapositioning of elements takes place at the other three carton corners. Because of the equidistance of aperture 13b on panel 13 and locking tab 20b from diagonal foldline 27, such aperture and tab are placed in registration with respect to one another when the corner structure of the carton of the invention is erect. Suitably, tongue 11b is so positioned along end outer edge 1141 as to arrive in registration with aperture 13b and locking tab 20b when they are in registration with each other. Then, the carton assembler, whether having human hands or mechanical, preferably automatic, means can apply pressure against the carton outside of tongue lllb, causing it to move into and through aperture 1311; against the carton outside of locking tab 17b; and, into and through the space left by such tab as it leaves the plane of panel 17 under such pressure. Having done the same thing at the other three carton corners, the assembler achieves a locked web corner carton or tray. For, the natural inclination of the material of locking tabs 17b, 18b, 19b, and 20b, particularly if such material is .papel'board, will be to resist the aforementioned pressure and to spring back into the planes of panels 17, 18, 19, and 20 when the pressure is released, thereby causing tongue wings 11g and 12g to imlpiu-ge against the carton insides of panels 17, 18, -19, and 20, since tongues and wings are suitably of a predetermined dimension that forbids their re passage through the narrower spaces left by the locking tabs and the narrower spaces left by the lockingtabs and the narrower apertures in panels 13,114, '15, and 16 without'extraneous manual or mechanical aid;

FIGURES 2 and 4 show the locking elements or devices of the present invention at that instant when the assembler has pressed the several tongues through the several apertures and spaces and before the several tabs have \perfected the locking. In use, the only difference in the carton is that, for instance, tongue 12b and tab 20b of FIGURE 4 would incline, rather than decline, from the horizontal.

Finally, as already noted, FIGU-R'El shows lid member 50 and flaps 51, 52, and 53. The use of these elements, is, of course, optional, but, if they are used, it is recommended to those skilled in the art to employ preprinted adhesive (-as reflected by the shaded areas on the blank of FIGURE 1) with them and, further, to provide a tear strip54 (see FIGURE formed by means of lines of weakness 55 and 56, e.g., perforations or slits, on flap 53 or some other portion of the carton so that it may be readily and conveniently opened by its ultimate con- SLllTlCI'.

What is claimed is:

1. A folding box of paperboard, the box comprising, in combination, a bottom panel; end wall panels articulated to opposite ends of the bottom panel; side wall panels articulated to opposite sides of said bottom panel; corner gussets articulated to said end'wall panels and to said side wall panels, respectively, each corner gusset comprising a pair of gusset panels articulated to each other along, and folded face to face at, a gusset fold line, said corner gussets lying on the inside of the box folded against the respective end wall panels; an interlock between each of said corner gussets and the respective end wall panel which the gusset overlies on the inside, said interlock comprising a substantially T -shaped tab formed in the end wall panel by two spaced cuts extending into the top edge of the end wall, said T tab being hinged to the remainder of the wall panel along a hinge substantially parallel to,

and below, the top edge of the end wall panel, and a pair of spaced external locking cuts extending into the top edge of the innermost gusset panel, said locking cuts being spaced from each other by a distance less than the width of the head of the T tab, said T-shaped tab extending from the end wall past said locking cuts and engag-ing with the head of the T the inside surface of said innermost gusset panel, thus lacing the end wall panel to the innermost gusset panel; a cover panel articulated to one of said side wall .panels along a cover hinge line; a cover front flap articulated to the cover panel along a fold line parallel to said cover hinge line; and cover end flaps articulated to the ends of the cover panel to overlie said endwalls and the said interlocks.

2. A carton produced from a blank comprising a substantially fiat rectangular unit having (a) a bottom panel bounded 'by vertical foldlines and horizontal foldlines;

(b) opposing end wall panels bounded by the vertical foldlines, the horizontal foldlines, and end outer edges along which means define inwardly extending tongues;

(c) first web corner panels bounded by the vertical foldlines, diagonal foldlines, and first corner outer edges along which means define inwardly extending apertures narrower along-the first corner outer edges than the tongues along the end outer edges;

(d) second ,corner panels bounded by the horizontal foldlines, the diagonal foldlines, and second corner outer edges along which means define inwardly extending locking tabs narrower along the second corner outer edges than the tongues along the end outer edges; and

(e) opposing side wall panels bounded by the vertical foldlines, the horizontal foldlines, and side outer edges in which the opposing end Wall panels and opposing side wall panels are-disposed perpendicularly to the bottom panel and to each other, the first web corner panels are disposed adjacently to the opposing end' wall panels and interiorly thereof, the second web corner panels are disposed adjacently to the first web corner panels and interiorly thereof, the tongues are disposed in the apertures and interiorly of the opposing end wall panels, and the locking tabs are disposed abuttingly against the tongues and interiorly thereof.

3. A carton in accordance with claim 2 where the apertures and the locking tabs have substantially the same dimensions.

4. A carton in accordance with claim 2 wherein the apertures along the first corner outer edges and the locking tabs along the second outer edges are disposed equidistantly from the diagonal '-foldlines immediately separating the apertures and tabs.

5. A carton in accordance with claim 2 wherein a lid member is connected along a vertical foldline to a side wall panel.

6. A carton in accordance with claim 5 where the lid member includes flaps disposed abuttingly against the end wall panels and means defining a tear strip in at least one of the flaps.

References Cited by the Examiner UNITED STATES PATENTS 2,846,132 8/ 1958 Carpenter 229-31 2,909,105 10/ 1959 Lawrence. 3,008,626 11/ 1961 Lawrence 229-35 X 3,054,550 9/ 1962 Comstock 22931 3,076,590 2/1963 Petryk et al. 2295 1 JOSEPH LECLAIR, Primary Examiner.

D. T. MOORHEAD, Assistant Examiner. 

1. A FOLDING BOX OF PAPERBOARD, THE BOX COMPRISING, IN COMBINATION, A BOTTOM PANEL; END ALL PANELS ARTICULATED TO OPPOSITE ENDS OF THE BOTTOM PANEL; SIDE WALL PANELS ARTICULATED TO OPPOSITE SIDES OF SAID BOTTOM PANEL; CORNER GUSSETS ARTICULATED TO SAID END WALL PANELS AND TO SAID SIDE WALL PANELS, RESPECTIVELY, EACH CORNER GUSSET COMPRISING A PAIR OF GUSSET PANELS ARTICULATED TO EACH OTHER ALONG, AND FOLDED FACE TO FACE AT, A GUSSET FOLD LINE, SAID CORNER GUSSETS LYING ON THE INSIDE OF THE BOX FOLDED AGAINST THE RESPECTIVE END WALL PANELS; AN INTERLOCK BETWEEN ECH OF SAID CORNER GUSSETS AND THE RESPECTIVE END WALL PANEL WHICH THE GUSSET OVERLIES ON THE INSIDE, SAID INTERLOCK COMPRISING A SUBSTANTIALLY T-SHAPED TAB FORMED IN THE END WALL PANEL BY TWO SPACED CUTS EXTENDING INTO THE TOP EDGE OF THE END WALL, SAID T TAB BEING HINGED TO THE REMAINDER OF THE WALL PANEL ALONG A HINGE SUBSTANTIALLY PARALLEL TO, AND BELOW, THE TOP EDGE OF THE END WALL PANEL, AND A PAIR OF SPACED EXTERNAL LOCKING CUTS EXTENDING INTO THE TOP EDGE OF THE INNERMOST GUSSET PANEL, SAID LOCKING CUTS BEING SPACED FROM EACH OTHER BY A DISTANCE LESS THAN THE WIDTH OF THE HEAD OF THE T TAB, SASID T-SHAPED TAB EXTENDING FROM THE END WALL PAST SAID LOCKING CUTS AND ENGAGING WITH THE HEAD OF T THE INSIDE SURFACE OF SAID INNERMOST GUSSET PANEL, THUS LACING THE END WALL PANEL TO THE INNERMOST GUSSET PANEL; A COVER PANEL ARTICULATED TO ONE OF SAID SIDE WALL PANELS ALONG A COVER HINGE LINE; A COVER FRONT FLAP ARTICULATED TO THE COVER PANEL ALONG A FOLD LINE PARALLEL TO SAID COVER HINGE LINE; AND COVER END FLAPS ARTICULATED TO THE ENDS OF THE COVER PANEL TO OVERLIE SAID END WALLS AND THE SAID INTERLOCKS. 